Karl Barth was well-known for his criticism of German nationalism as a corrupting influence on the German protestant churches in the Nazi era. Defining and recognising nationhood as distinct from the state is an important though underappreciated task in Barth's theology. It flows out of his deep concern for the capacity for nationalist dogma - that every nation must have its own state - to promote warfare. The problem motivated him to make his famous break with German liberal protestant theology. In this book, Carys Moseley traces how Barth reconceived nationhood in the light of a lifelong interest in the exegesis and preaching of the Pentecost narrative in Acts 2. She shows how his responsibilities as a pastor of the Swiss Reformed Church required preaching on this text as part of the church calendar, and thus how his defence of the inclusion of the filioque clause in the Niceno-Constantinopolitan Creed stemmed from his ministry, homiletics and implicit missiology. The concern to deny that nations exist primordially in creation was a crucial reason for Barth's dissent from his contemporaries over the orders of creation, and that his polemic against 'natural theology' was largely driven by rejection of the German liberal idea that the rise and fall of nations is part of a cycle of nature which simply reflect divine action. Against this conceit, Barth advanced his famous doctrine of the election of Israel as part of the election of the community of the people of God. This is the way into understanding the division of the world into nations, and the divine recognition of all nations as communities wherein people are meant to seek God.